Paper bags having airtight areas to facilitate automatic bag feeding



May 31, 1960 J. D. HELM PAPER BAGS HAVING AIRTIGHT AREAS TO FACILITATE AUTOMATIC BAG FEEDING Filed Oct. 28, 1957 INVENTOR. .5104 D. HELM ArTaR/vs YJ ilnited States Patent Gee assess? Patented May 31, 1960 PAPER BAGS HAVING AIRTIGHT AREAS T FACILITATE AUTOMATIC BAG FEEDING Jack D. Helm, 6444 Newton Ave. S., Minneapolis, Minn.

Filed Oct. 28, 1957, Ser. No. 692,822

'3 Claims. (Cl. 229-55) This invention relates to new and useful improvements in flexible walled bag bodies, and more specifically to the treatment of limited areas of the usual porous walls of such bags to render said areas non-porous to render the empty bag bodies capable of being expeditiously fed from the supply source to the usual filling spout of a bag filling machine by the usual vacuum cups of a conventional bag feeding mechanism.

It is well known in the packaging industry that many automatic bag filling machines are now equipped with vacuum type bag feeding mechanisms utilizing vacuum cups for engaging and picking up the empty bag bodies from a stack of bags and successively delivering them to the filling spout of the bag filling machine.

Paper bags, as now commonly made for use in the packaging industry, are usually made from flexible paper stock which is more or less porous whereby when a bag 7 body is applied to the filling spout of a bag filling machine, air entrained with the material as it is delivered into the bag body may escape to the atmosphere through the pores in the bag walls and thus prevent spouting of the material between the walls of the bag top and the periphery of the filling spout. Bag bodies constructed of such porous material are extremely diificult to feed or deliver, one at a time, to the usual filling spout of a bag filling machine by the use of vacuum cups because of the porosity of the bag walls and the suction through them.

By rendering restricted areas of the bag walls non porous, as herein featured, the empty bags, as they are successively removed from the stack of bags and transferred to the filling machine by the usual vacuum cups of the bag feeding mechanism, each bag may be temporarily brought to rest in a position beneath the filling tube, from whence it is subsequently moved onto the filling spout or tube by suitable means, not shown in the drawings. In some instances, each bag body positioned beneath the filling spout or tube may have its opposed walls completely collapsed and gripped between the two vacuum cups. If the areas where the vacuum cups above mentioned engage the bag walls are not nonporous, the opposed bag walls cannot be separated to open the bag, as the vacuum cups would oppose each other. Therefore it is necessary that the wall portions engaged by the vacuum cups be rendered non-porous so that air may not be drawn through the pores of the wall portions engaged by the suction cups.

As is well known in the art, it is of utmost importance that the bags be fed uninterruptedly from the storage magazine or rack to the bag filling machine, one at a time. The present invention makes this possible and definitely assures the operator that the bags may be successively fed, one at a time, to the bag filling machine, in position to be readily slid upwardly over the lower end of the bag filling tube to receive a charge therefrom.

To accomplish such positive feeding of the empty bag bodies from a storage magazine into position to he slid onto the lower end of a filling tube by conventional vacuum cups, the restricted areas of the bag walls are treated to render them non-porous, whereby the usual vacuum cups of the bag feeding mechanism may readily pick up the bags and deliver them to the filling machine, one at a time.

The present invention pertains more particularly to the treatment of limited areas of the walls of porous bag bodies to render such limited areas non-porous, whereby the usual vacuum cups of a conventional vacuum type bag feeding mechanism may efficiently feed the empty bags, one at a time, to the filling spout of a bag filling machine.

An important object of the present invention therefore is to render limited areas of the porous walls of a bag body substantially non-porous, whereby such limited areas will resist the passage of air therethrough sufliciently to assure that the usual vacuum cups of a conventional bag feeding mechanism may positively grip the bag walls in the operation of feeding the empty bags, one at a time, to the bag filling tube.

A further object is to provide a bag body comprising a plurality of porous walls having limited areas of certain of its walls treated with a suitable non-porous material thereby to seal the pores in said limited areas whereby the usual vacuum cups of a conventional bag feeding mechanism may be applied thereto in the operation of successively feeding the bags from a stack of bags or a magazine to the usual filling spout of a bag filling machine. Other objects of the invention reside in the manner of applying the non-porous coating to limited areas of inner surfaces of single-ply bags and to the inner surfaces of the outer plies of multi-wall bag bodies; in the application of such non-porous coatings or elements to either the outer or inner surfaces of the opposed walls of a bag body; said non-porous areas being so located on the bag walls that they may readily be engaged by the usual vacuum cups of a conventional bag feeding mechanism in the operation of successively feeding the bags to the filling machine and opening the bag mouth to facilitate slipping the bag top over the filling tube, without altering the construction of said mechanism.

These and other objects of the invention and the means for their attainment will be more apparent from the following description taken in connection with the accom panying drawings.

In the accompanying drawings there has been disclosed a structure designed to carry out the various objects of the invention, but it is to be understood that the invention is not confined to the exact features shown, as various changes may be made within the scope of the claims which follow.

In the drawings:

Figure 1 is a view showing a side elevation of a conventional paper bag wherein the non-porous areas are substantially square in configuration;

Figure 2 is a view similar to Figure 1, but showing non-porous areas of relatively greater size than those shown in Figure 1;

Figure 3 is a perspective view of a multi-wall bag body, partially broken away to show the application of the non-porous coating to the inner surface of the outer plies of said walls; and

Figure 4 is a vertical sectional view on the line 44 of Figure 3.

In the selected embodiment of the invention herein disclosed there is illustrated in Figure l, a bag body 2 of conventional construction, comprising single ply walls.

An important feature of the present invention resides in the application of a non-porous material or coating 3 to restricted areas of the opposed bag body walls, whereby such areas are rendered substantially non-porous to permit the usual vacuum cups of a conventional bag feeding machine to be applied thereto in the operation of successively feeding the bags from a stack of bags to the filling spout of the bag filling machine, as is well known inthe trade I V .In Figure l the restricted non-porous areas 3 ,are shown having their marginal edgesspaced well inwardly from the corresponding edges of the ,bag body. The coating material, which may be of any suitable form applicable for the purpose, is preferably applied to the inner surfaces of the side walls of the bag body, as indicated in Figure 1, wherein aportion of the forwardly facing side wall of the bag body has been broken away to more clearly show the location of the non-porous material on the inner surfaces of the bag walls.

Obviously, the non-porous material may be applied to. the outer surfaces of the bag walls, but such application may interfere with the subsequent application of printed matter to, the bag, body and may also affect the general appearance of the bag. The material utilized to render the restricted areas 3 of the bag bodies nonporous may be in the form of a solution applied to the bag body in liquid form which will penetrate into the pores of the bag walls and completely seal such restricted areas against the passage of air therethrough, when a suction cup is applied to such treated areas. It may also be possible to apply a pre-formed thin sheet-like film of a suitable non-porous material directly to the walls of the bag body, or to utilize any other suitable material which will adequately seal the pores in the restricted areas 3 of the bag walls, as above described.

The present invention is not concerned with the composition or nature of the coacting material utilized for rendering the restricted areas of the bag walls nonporous. It may be mentioned, however, that the coating material may be applied before, during, or after. bag manufacture without departing from the scope of the invention. It is also to be understood that the coating material'may in some instances be extended the full width .of the bag walls.

. In Figure 2 there is shown a bag body 4 in which the restricted non-porous area 5 is extended downwardly a substantial distance the length of the bag body. The dotted lines indicate the restricted areas 5 of the bag body which are so treated- In Figures 3 and 4 the invention is shown applied to a bag body 6 having mu ti-ply walls. In such bags the non-porous material is preferably. applied to the inner surfaces of the outer plies of the opposed walls of the bag body, as indicated at 7 in Figure 3, whereby the non-porous areas are completely hidden from view and do not interfere with the subsequent application of printed matter to the exterior surfaces of the bag walls. The present, invention makes it possible to retain the usual porous feature of the bag walls to permit uninterrupted escape of entrained air from the bag body during thefilling operation, .as in the past, and at-the same time, it now renders such bags capable of being successively fed to a bag filling machine by a conventional bag filling mechanism of the vacuum cup type.

The coating solution must be of such a nature as to 4 seal the pores in the portions of the bag body walls defining the restricted areas 3, 5 and 7, whereby air cannot pass therethrough. The non-porous coating solution may be plastic or of any other suitable type that readily lends itself to be sprayed, brushed or otherwise applied to the surfaces of the bag body walls, or it may be in the form of independent pre-formed sheet-like elements having means whereby they may readily be applied to the bag walls by suitable equipment.

The essential feature of the invention, as hereinbefore stated, resides in the application to restricted areas of the opposed walls ofa bag body of a suitable non-porous material, thereby to render the bags capable of being fed or moved from one place to another by the use of conventional vacuum type bag feeding mechanisms.

The invention may be embodied in other specific forms without departing from the essential characteristics thereof. Hence, the present embodiments are therefore to be considered in all respects merely asbeing illustrative and not as being restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all modifications and var: iations as fall within the meaning and purview and range of equivalency of the appended claims are therefore intended to be embraced therein.

I claim as my invention:

1. A bag body comprising a plurality of flexible walls constructed of a porous material whereby air entrained with the material delivered into the bag body may escape therefrom to the atmosphere through the pores in the bag walls, and at least one of the walls of the bag body having a non-porous coating material applied to a limited area thereof to which the usual vacuum cup of an auto.-

matic feed mechanism may be applied in the operation of successively feeding the empty bags from a stack of bags to a desired position relative to the usual filling tube of a bag filling machine.

2. A bag body comprising a plurality of flexible per,- ous multi-ply walls through which air entrained with material delivered into the bag may escape to the atmosphere during the bag filling operation, and a non-porous coating material of limited size being applied to the inner surface of the outer ply of the opposed walls of the bag body, thereby to render ,said areas non porous to facilitate the application thereto of the usual vacuum cups of an automatic bag feeding mechanism. 7

3. A bag body comprising a plurality of flexible porous. walls to which air entrained with material delivered into the bag body may escape to the atmosphere during the bag filling operation, and a non-porous material being applied to limited areas of the opposed walls of the bag body, thereby to render said wall' areas non-porous to. facilitate the application thereto of the usual vacuum cups of an automatic bag feeding machine.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,938,657 May 31, 1960 Jack D, Helm It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below,

In the grant, lines 1, 2 and 3, for "Jack D. Helm, of Minneapolis, Minnesota," read Jack D. Helm, of Minneapolis, Minnesota, assignor to Bemis, Bro, Bag Company, of Minneapolis, Minnesota, a corporation of Missouri, line 12, for "Jack D, Helm, his heirs" read Bemis Bro, Bag Company, its successors in the heading to the printed specification, line 4, for "Jack D. Helm, 6444 Newton Ave S, Minneapolis, Minn," read Jack D, Helm, Minneapolis, Minn,, assignor to Bemis Bro. Bag Company, Minneapolis, Minn., a corporation of Missouri Signed and sealed this 20th day of December 1960.,

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents 

